Method of completing wells



April 19, 1938. c Q BROWN 2,114,521

METHOD OF COMPLETING WELLS Filed June 8, 1956 2 Sheets-Sheet 1 I3 22 I e 22 F i .2 C.C.BROWN mm 5 Ms. W

Patented Apr. 19, 1938 UNITED STATES PATENT OFFICE 2,114,521 METHOD or COMPLETING WELLS Cicero C. Brown, Houstom'Tex. Application June s, 1936, Serial No. 84,073

6 Claims.

My invention relates to a method of completing wells for production and has particular reference to the cementing and the steps taken to complete the well after the cementing operation has been performed.

It is an object of the invention to devise a method of cementing the well so as to entirely close off the entrance ofany fluid whatever to the well bore and to then open up communication from the formation through the wall of the well to the interior thereof.

It is a further object to provide a means for cementing the well without the use of an unnecessary amount of cement. I contemplate forcing the cement around the lower end of the casing or liner without the necessity of filling the whole interior of the casing with cement in so doing.

It is a further object of the invention to prevent the mixing of the cement and the mud in the well and thus avoid impairing the efliciency of the cement.

I further desire to arrange the completing of the well so that there will be a minimum of danger of blowout in the finishing operations.

1 is a central longitudinal section through a well casing showing a portion of the setting tool partly in elevation and partly in section. Fig. 2 is a similar view showing the lower end of the casing or liner with the back pressure valve and setting sleeve in connection therewith.

I have illustrated my invention as adapted for use where a casing is set in the well and the Well extended beyond the casing down tov the producing formation and a liner is set from the casing down to the lower end of the well. This is a very common method of equipping the well, but I Wish it to be understood that the invention is not confined to the use of a casing and liner, it being possible to set the liner all the way from the surface and where such construction is used the method of handling the well is the same.

With referenceto Fig. 5, I have shown the well as equipped with a casing l, which reenforces With reference to the drawings herewith, Fig.

the wall of the well down to the lower end of the casing, This casing has been cemented as shown at 2 so as to close off the entrance around the lower end of the casing of any fluid from above the same outside the casing. The well has then been drilled down through the casing making a hole of small diameter as shown at 3. In this smaller hole a liner is set. The hole has been drilled down through a producing formation which is indicated at I, and the liner shown at 5 extends through the formation and has at its lower end a set shoe 6 of ordinary construction. In lowering the liner through the casing to its position at the bottom of the well I employ the setting tool shown best in Fig. 1. A string of pipe I, which may be a'drill stem, is secured at its lower end to a collar 8. This collar is internally threaded at its lower end for connection at 9 to a nipple l0.

The nipple l0 extends beyond the collar a suitable distance and is threaded to receive a clamping collar ll. Above the threaded area the outer face of the nipple is provided with an annular shoulder l2, which is upwardly inclined to furnish a support for a plurality of latching dogs 83. Spaced above the shoulder l2 a collar I4, is

screwed on the outer surface of the nipple and is held rigidly in position by a locking screw iii. The lower end of the collar it has an outer, downwardly extending flange i 6 under which the upper'ends of the latching dogs may engage, as will be understood from the drawings.

on the outer surface of the collar 86 is an annular recess to receive a packing ring ll of rubher, or similar compressible packing material, the upper end of which is grooved so as to be expanded by fluid pressure from above.

.detween the collar i l and the coupling 8 1 provide an anti-friction bearing race including a lower ring it, an upper ring l9, and an intermediate row of balls 26.

The latching dogs l3 have their lower ends extending downwardly below the shoulder and have outer downwardly inclined shoulders ii to be clamped between the upper tapered surface 22 of the clamping collar H and the interior of the setting collar with which it is to engage.

The setting collar is shown best in Fig. 2 but reference is made particularly to Fig. 3 in showing the engagement between the setting tool and the setting sleeve. The setting collar has an upwardly extending barrel 23 and its lower end is inclined inwardly and reduced both in external and internal diameter. At its lower end it is extended outwardly and threaded at 24 for engagement within the set shoe 3. i

The upper end of the barrel 23 hasa seat 28 upon which the lower ring ll of the'bearing race may engage and be supported. Spaced below this upper end there is an interior shoulder 21 beveled to engage with the outer shoulders 2i upon the dogs 13.

Below the Shoulder, and spaced therefrom is an inwardly extending key or ridge 28 which is adapted to engage with outwardly extending key or ridge 29 upon the clamping collar II.

The interior of the reduced lower end of the setting sleeve is formed with a packingmember 30 having'its lower end cleft to permit the en? trance of pressure fluid to assist in sealing the same against the inner lower end of a nipple l0. Below the sealing ring 30 and within the cylindrical portion of the setting sleeve. is an annular recess 3| in which is housed a spring ring 32. Said ring is to be understood as a split ring similar to the ordinary metal piston ring. Its upper end is beveled inwardly so that when it is engaged by a plug such as shown at 33 it will be forced outwardly into the recess to allow the passage of the plug and then will move inwardly to engage within a latching recess 3| in the plug.

The lower end of the setting sleeve is formed into a seat to receive theback pressure valve 34, which is of ordinary construction and need not be particularly described. It is held normally within the seat by a spring 35.

The set shoe 8 with which the lower end of the setting sleeve is engaged is connected to the lower end of the liner and has a lower forwardly projecting blade 25 thereon to engage the formation and resist rotation of the liner. There is a central Opening 36 through which fluids may pass downwardly past the back pressure valve.

The upper end of the liner may be equipped with a packer as shown at 31 in Fig. 4, or the packer may be omitted as shown in Fig. 5. Where a packeris employed it may be set when the liner is in position to close the space between the lower end of the casing and the upper end of the liner.

When the packer such as is shown in Fig. 4 is employed the setting string has thereon a packer setting device such as is shown at 44. This setting device has thereon dogs 45 which are adapted to be moved outwardly to engage with the upper shoulder 46 about the packer and thus allow the exertion of pressure upon the upper end of the packer to compress it in the usual manner.

In assembling the setting tool within the liner preparatory for lowering the liner into position the setting tool will have the parts thereon in position as shown in Fig. 1. The setting tool will be lowered into the setting sleeve arranged as shown in Fig. 2. When the setting tool has reached the seat in the setting sleeve it will be rotated to bring the laterally extending keys or lugs 29 on the clamping collar ll into engagement with the key 28 on the interior of the setting sleeve. The setting tool will then be rotated in a lefthand direction so as to screw the clamping collar ll upwardly beneath the lower end of the dogs l3. This will move said lower end outwardly and will clamp the upper shoulders 2| on the dogs against the shoulder 21 on the setting sleeve. The setting tool will thus be locked in position rigidly against the sleeve as will be understood from Fig. 3. It will be noted that -a,114,sa1

a seal is formed between the setting tool and the setting sleeve due to the upper packing ring II and the lower packing ring 33. There will be no escape of liquid around the connection between the setting tool and the sleeve, as-will be clearly understood. The anti-friction bearing at 20 is of use in the rotation of the setting tool in movingthe clamping collar ll into position such as has just been described. The lower ring I! of the raceway will set frictionally against the upper end of the setting sleeve and will be held stationary while the tool is being rotated. This furnishes a support which limits the downward movement of the setting tool to the proper level and also allows more ready rotation of the setting tool while the clamping collar II is being moved into clamping position. With this rigid connection between the setting tool and the lower end of the liner thesetting tool may be employed to lower the liner downwardly into position at the bottom of the well. Mud may be pumped downwardly through the liner during the operation and when the bottom has been reached the circulation of the mud will serve to clear away the material at the lower end of the well so that the liner may be properly seated.

When the parts are in this position I cement through the setting string and around the lower end of the liner. In doing this I prefer to place a charge of cement of the proper amount into the upper end of the setting string and above the mud in the string. On the upper end of the charge of cement I place a plug such as is shown in Fig. 3 at 33. This plug forms a piston which is a separating barrier between the cement and the mud which is pumped in above the plug. The pump pressure forces the cement ahead of the plug and downwardly around the lower end of the liner and upwardly outside thereof. I contemplate pumping a suillcient charge to displace all the mud at the lower end of the well and force the cement upwardly the full length of the liner and around the lower end of the casing, as shown in Fig. 5. Where this is done the cement serves to pack of! between the liner and the casing at the upper end of the liner and to entirely seal against all liquids from the lower end of the well. When the plug 33 reaches the lower end of the setting tool it will be engaged by the ring 32 and will be held in position to close the lower end of the liner.

The setting tool may then be released and removed. This is done by rotating the setting string in the reverse direction to move the clamping ring ll downwardly away from the dogs l3 so as to release the same and then the setting tool may be drawn upwardly from the well.

The cement is allowed to set until it is hard and the next operation consists in perforating the liner at the level of the producing formation 4. There are many devices for perforating casing. I contemplate using any preferred form of perforator preferably what is called a gun perforator, which forms openings as shown at 38 in Fig. 5, said openings extending radially outwardly from the liner and through the wall of cement adjacent thereto. This allows the fluid from the producing formation to enter the well through the perforations.

The well is then ready to flow and if a strainer is desirable a strainer will be set. In some formations the use of a strainer will not be necessary. In Fig. 5 I have shown a strainer 39, as having been connected at the lower end of a short string of pipe 40 and lowered into position with the set shoe ll thereon seated at the upper end of the setting sleeve 23. At the upper end of the pipe 40 I have shown a canvas packer 42 which may be employed to close the space between the pipe 40 and the interior of the liner. This packer and its operation is well known in the art and forms no part of the present invention and need not be further described. A flow tube 43 may then be lowered downwardly into the interior of the strainer and the well is ready for production.

It will be seen that with my present method of completing the well it is possible to employ the cement most efliciently. Under other methods of cementing which are now common it is necessary to fill the whole interior of the liner with cement and force this large volume of cement downwardly through the large volume of mud which it displaces. In the present method only the cement is circulated through a setting string of much smaller diameter and the smaller diameter of the setting string makes it possible to more effective- 1y handle the cementing operation without waste. The mud which is below the cement is moved downwardly through the string and outwardly into the well and will be moved upwardly ahead of the cement and will not mix with the cement to such an extent as to impair the cementing operation as frequently occurs in the previous methods. I find that much more consistent and reliable results are obtained by this method.

Further, the cementing of the full length of the liner up above the producing formation serves to effectively seal of! the entrance of fluids into the well to mix with the production from the producing formation. When the liner and the wall of the cement has been perforated to allow the entrance of production to the well, the well may be more easily controlled to prevent danger of blowout. The method is therefore more easily performed and is less wasteful of cement and more reliable in its results than other methods now in common use.

What is claimed as new is:

l. A method of finishing a well for production including; cementing a casing in the well, drilling down through the cement and into a producing formation, setting a liner in the well and simultaneously extending a fluid conducting line through said casing and liner to seal with the lower end of said liner, forcing cement through said liner and around the lower end of said liner upwardly to cement the outer face of said liner and fill the space between said liner and casing, maintaining the interior of the liner free of cement, hardening said cement, perforating said liner and cement at the level of the producing sand and setting a screen within said liner.

2. A method of finishing a well for production including; cementing a casing in the well, drilling down through the cement andinto a produc ing formation, setting a liner in the well and simultaneously extending a fluid conducting line through said casing and liner to seal with the lower end of said liner, forcing cement through said line and around the lower end of said liner upwardly to cement the outer face of said liner and fill the space between said liner and casing, withdrawing said line, hardening said cement, and perforating said liner and cement at the level of the producing sand so as to allow entrance of fluid therefrom to said liner.

'3. A method of finishing a well for production, securing a fluid conducting pipe in sealing engagement with the lower end of a liner and lowering the liner to position in the well with said pipe, forcing cement through said pipe and upwardly outside the liner to a level above the producing formation, discontinuing the cementing to prevent the entrance of cement to the interior of said liner, allowing said cement to set, detaching and removing said pipe, thus leaving the interior of said liner clear of cement, puncturing said liner and said cement at the level of the producing formation and then setting screen in the liner.

4. A method of finishing a well for production, securing a fluid conducting pipe in sealing engagement with the lower end of a liner and lowering the liner to position in the well. forcing cement through said pipe and upwardly outside the liner to a level above the producing formation, closing the lower end of the liner above the cement, maintaining the interior of said liner clear of cement, allowing said cement to set, removing said pipe, puncturing said liner and said cement at the level of the producing formation and then setting screen in the liner.

5. A method of finishing a well for production, securing a fluid conducting pipe in sealing engagement with the lower end of a liner and lowering the liner to position in the well, preserving said sealing engagement while forcing cement through said pipe and upwardly outside the liner to a level above the producing formation, maintaining the interior of said liner, clear of cement, allowing said cement to set, closing the lower end of said liner above any opening therein, removing said pipe, puncturing said liner and said cement at the level of the producing formation and then inserting a flow line for the fluid from the well.

6. A method of finishing a well including connecting a setting string in sealing engagement with the lower end of the liner and setting a liner in the well, preserving said seal while forcing cement through said setting string around the lower end of said liner and cementing the liner in positiomplugging the lower end of the liner above any opening in the end thereof, and withdrawing the setting string.

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